Roller for sugar-cane mills.



H. W. AITKBN.'

ROLLER POL SUGARGANE MILLS.

cn.. PHoT0LlTHc.. WASHVNC VDN. "1. C

'bnfrrnn srarns PATENT onirica.

nnen WALLACE Airinn, or etaseew, sco'rLANn.

Lifte-.26.

Speccation of LettersPatent. `1333115911{3Q-dGmb, 2q), 1914.

Application led July 29, 1913. Serial No. 781,730.

T0 all 'whom it may Con/cern Be it known that HUGH WAL-LAGE Ai'rirEN, a subject of the Kino' of 'Great Britain and Ireland, residing at 147 Bath street, Glasgow, Scotland, have invented certain new and useful improvements in Rollers for Sugar-Cane Mills; and l do hereby declare the following to bea full, clear, and exact description of the invention, such as will enable others skilled in the art to which it vappertainsto make and use the same, reference being had to the accompanying drawings,

and to letters or figures of reference markedy thereon, which form a part of this specification. 1

My invention relates to rollers .of sugar cane mills. rfhe rollers of sugar cane mills are usually constructed of cast iron casings or shells mounted on wrought iron or steel shafts. The casings are usually cast hollowV and bored out to receive the shaft. They are usually either forced on to the shaftl by hydraulic pressure orare expanded by heat and shrunk on to the shaft. They usually make contact with the shaft at the endsonly or at the ends and middle.` They are secured on the shaft and prevented from rotating relatively thereto by means of fitted keys driven into keyways parallel to the axis of the shaft. ri"he loads which the rollers have to carry are very severe, and shafts often break, frequently just inside the roller casting or casing, the fracture being caused by the excessive bending and torsional strains to which the shaft is subjected. Fracture of the shaft inside the casing is also often caused by the juice finding its wav into the hollow between the casing and the shaft,A

due in seine cases to the ke s not beine' properly fitted in the key-ways) and there fermentine ndcorrodino the shaft and the u t) l u part of tue roller castingor casing bearing on it. falso, rollers in time get worn on the surface and either the roller casing must bel replaced or a complete newroller, i. 0.,?'casing and shaft be provided. .The withdrawing of the fractured shaft from the roller casing and the insertion of a new shaft in the old easing, and likewisethe insertion ofl an old shaft in a new casing, are serious mat--y ters and difficult to perform at the `sugar factory.

The object of the present invention is to produce a roller with a shaft which from its dimensions is unlikely to break, and with a The shaft should be of material-say steel or wrought iron-which is of great tensile strength and is also very tough.l The sleeve, which is preferably of very'hardandi open-l grained cast iron, is bored with an internal diameter slightly less than the external dia-meter of the shaft and is 'preferably inountedon theishaftby being expanded by the thickness of the sleeve kbeing small coinl pared with the diameter of the shaft.r

heat "and slipped'ywhenliot onto the shaft" and shrunk on. Hydraulic orother pressure. may, however, be'employed if desired, with or without heat, to `force the sleeve onto the shaft; but it is an essential feature-ofmy invention Vthat the sleeve when cold is secured on the shaft by friction caused bystrain, the

sleeve being subjected to tensile strainy and the shaft to compressive strain. l' consider that the sleeve should be bored from about 0.06 per cent. less than the external dia-meter of the shaft but as the texture,- tensile strength and other properties of they sleevey vary according as it is made of hard iron suitable for grinding hard canes or soft iron suitable for grinding soft canes, the percentage difference betweenthe bore of the sleeve and the diameterof the shaft may be as high as 0.1 for very iard iron and 0.02 for soft iron. The relatively largediaineter ofk the shaft not only provides ay relatively great surface lof contact between sleeve and shaft and so augments Athey aggregate friction' but also furnishes a relatively `great leverage for :the friction. `The moment of frictionalgrip,

or'thevfrictional torque, is thus increased for two-reasons. In order kto stillfurther augment the` frictional gripl[ yprovide a relatively great (axial) length of contact surnearlyl the "whole, inclosed' surface of the shaft andthat' the length-or aggregate ico face.l I prefer tov arrangethattlie whole, or rnearly thefwhole, yinterior surface of the sleeve'. makes contact with the whole, or

tudinal section oL lengtl --of the Contact surfacel shalll be not less than one and a. haltl times the external diameter-L c., the 'diameter ot the crushing surface-of the roller.

By constructing a roller as above mentioned, it is possible to dispense With 'itted as heretofore used, as, when the roller is cold, Y tion is quite sul'lieient to prevent slip between sleeve and shaft even uuder the most adverse conditions of load. rEhe absence oi' fitted lreys and the relative lightness or the sleeve render it compara tivly easy te place the latter on its shaft; and a sleere, when broken or much Worn, can be readily and at comparatively small cost replaced by a neuv one. The shaft, owing to its excessive strength, is unlikely to be bent or broken.

in order to successfully apply my invention and get iull adfantage therefrom, I

keys

consider Vt desirable that the diameter ot shaft Where inolosed by the sleeve rn n.

ahould be between G5 per Cont. and 85 per fent. ot the external. diameter of the sleeve ferieludmg ila. ges), although it might be possible to Werl-z sith `very slight risk and partly secure the advantages of my inveir tion with a sha't diameter slightly less than per Cent. et the sleeve diameter but certainly not ess than per cent.; and, if the were of very tough material, it might be possible Without much rislr to exceed S5 per cent.

llhe aeeoirpa ying drawing is a longia roller-according to my intention.

a is the shaft provided with portion 0 of enlarged diameter between the bearings e, e. Y

b is tbe sleeve siti ited on this enlarged portion. The sleeve may be bored or one internal d' er .i ghout, or it may be bored with one or more steps such as (Z, and 'he shaft mtwhine-l with a corresponding shoulder or shoulders. rEhe latter construetion assists in the placing olf the sleeve on the shaft. N

Eis the roller may sometimes be subjected to the action of hot Water in order to assist in the expression of the juice after the irst crushing of the cane; and, as the sleeve may therefore get heated before the shaft and thus be 'temporarily at a higher temperature tl an the shaft, there may be al tendency to reduce lthe rietional grip ol the sleeve on the shaft. ln order to obviate any chance 01c slip occurring on such occasional may Copies of this patent may be obtained for ve 'cents each, by addressing the Commissioner provide pins which are placed in holes bored in the sleeve and shaft, for example, as shoun at f, in the drawing. These pins may be'either screwed or dropped into place; and plugs such (l, g of the same material as the sleeve may, if necessary, be screwed in alter them and made Y[lush with the outside of the sleeve. lt is to be understood that these pins are only intended to aet for short in rvals of' time as the shaft ,vill quickly at in the saine temperature as the sleeve; and, moreover, the temporary stresses-if anyto which the pins are subjected cannot be great.

thus described my invention, What l claim as i eu and desire to secure by Let- 'herewith and of very tough material and great tensile strength, a sleeve of veryY riterial in ifrictional engagement with said enlargement and o'i greater length than its diameter so to provide suilcient grippingsurliace and stillness and through said enlargement prevent undue stresses and strains in the shaft and sleeve at the ends ol the latter` and the diameter ot' said enlargement being not less than approximately 60% nor more than approximately 90% of the external diameter ol said sleeve, whereby adequate strength is imparted to said shaft and sleeve.

f2. A roller for crushing sugar cane, comprising a sha'lt having an enlargement integral thereuf'ith and of very tough material and great tensile strength, a sleeve of very hard material in frictional engagement with aid enlargement and or greater length than its diameter so as to provide su'llieient gripping surface and stiilness and through said enlargement prevent undue stresses and strains in the shaft and sleeve at the ends of the latter, and the diameter of said enlargement being not less than approximately 60% nor more than approximately 90% and the length being not less than approximately 1550% of the external diameter of' said sleeve, whereby adequate strength is imparted to said shaft and sleeve.

ln testimony whereof l have signed my name to this specification in the presence of two subscribing Witnesses.

HUGH lALLCE ATKEN.

lltnesses ROBERT MORRISON NmLsoN, Fimo lilmoLnroN.

of retreats, 

